Method of separating laminæ of mica.



UNITED STATES ATENT; OFFICE.

RIOHARD W. HEARD AND RICHARD A. L. SNYDER, OF rir'rsnunarnnn- SYLVANIA,ASSIGNORS TO THE MIOA MACHINE COMPANY, or rrr'rs- BURG, PENNSYLVANIA, ACORPORATION.

METHOD OF SEPARATING LAMlN/E OF MICAu SPECIFICATION forming part ofLetters Patent No. 686,929, dated November 19, 1901. Application filedApril 24, 1901. Serial No. 57,261. No specimens.)

To all whom it nmy concern.-

Be it known that we, RICHARD W. HEARD and RICHARD A. L. SNYDER, citizensof the United States, residing at Pittsburg, in the county of Alleghenyand State of Pennsylseparation of the laininzn of mica, whether by handor by machinery, has always heretofore involved the employment of thinblades. While this means does not involve much loss when the mica has agood cleavage, the separation into very thin laminae is slow,andtherefore expensive. When the mica has a poor cleavage, the waste when ablade is employed is very large.

The invention described herein consists, generally stated, in effectingan opening up of the laminae, and by this term is meant such a lesseningof the cohesion of the lamina: or releasing or reducing the bond whichnaturally unites adjacent lamina: of mica as will permit the entrance ofa fluid between adjacent lamimc and then charging the spaces thus formedwith a fluid.

The invention further consists in treating the mica as above and thensubjecting the same to pressure, whereby the fluid is caused to spreadout and act as a wedge to effect a more complete separation of thelamime.

The invention is hereinafter more fully described and claimed. i

In the accompanying drawings, forming a part of this specification,Figure 1 is a diagrammatic view of a form of apparatus for the practiceof our invention, and Fig. 2 is a similar view of a modification of theapparatus.

In the practice of the invention the sheets or blocks of mica aresubjected to a treatment which will open up the laminae suiticiently topermit of the entrance of a. fluid between the laminzc. \Vhile thistreatment will if repeated often eifect a good separation of laminae, amore perfect separation can be effected by opening up the laminae topermit pressure will cause a spreading or difiusion of the fluid and byits mechanical or wedging action will effect a separation of the laminmfrom each other without injury thereto.

A desirable means for carrying out the invention consists in heating asheet or block in a furnace 1 or in any other suitable manner and thenimmersing the same in a liquid, as water,in a basin or tank 2. Theheating produces such a change in the natural relation of the lamina;that when immersed in the liquid the latter will permeate the sheet orblock entering between laminzc to a greater or less extent. By repeatingthe heating and immersion a number of times the laminae will be entirelyseparated from each other; but

a more rapid and effective separation can be produced if the sheet orblock when charged with liquid is subjected to pressure, preferably bypassing it between rollers 3. When pressure is applied, the liquid willbe caused to spread, and,acting like a wedge,will effect a splitting orseparation of laminae. In addition to its separating action the'liquidseems to act as a lubricant, so that by subjecting the sheet or block toa rubbing action, as by rotating the pressure-rollers in oppositedirections or at diiferent speeds in the same direction, the laminaewill slip along each other, By repeating these operations-i. e.,heating,

subjecting to pressure, and rubbing-an exceedingly fine subdivision ofthe mica can be obtained' The preliminary opening up of the laminae canbe eifected by placing the sheets or blocks in a. chamber, exhaustingthe air, 850., from the chamber, then immersing the exhausted sheet orblock in a liquid, and passing'the liquid-chargedblocks through betweenrollers. A convenient apparatus for the carrying out of this methodconsists in shell 4, arranged over a receptacle 5,containing the liquid.The mica is placed on a tray 6, which is movably supported bya rod 7.The shell is connected to a suitable vacuum-pump and is provided with avalved inlet 8 for air. While the air we is being exhausted the tray isheld abofithe liquid, and as soon as the desired vacuum is obtained thetray is pulled down into the 'liquid, the inlet-valve is opened, theshell removed, and a new charge placed on the tray. If necessary, themica can be treated several times before removing it from the tray.

. While not stated as a fact, there seems to be a fluid between thelaminae of mica in a natural state and that this fluid is expanded ordriven out when mica is heated or placed. in a vacuum and that the fluidis replaced by the liquid when immersed therein. It may be that the heatacts in a different-manner from the vacuum. Howsover that may be thereis such an opening up of the lamina: in both cases as to permit of theentrance of water, which will serve to more effectively open up the micawhen it is subjected to pressure.

We claim herein as our invention- 1. As an improvement in the art ofseparating laminae of mica, the method herein described, which consistsin opening up the 1amime of a piece of mica and then charging theopened-up piece with liquid, substantially as set forth.

2. As an improvementin the art of separating laminae of mica the methodherein described, which consists in heating up a piece of mica and thencharging the same with a liquid, substantially as set forth.

3. Asan improvement in the art of separating the laminae of mica, themethod herein described, which consists in opening up the laminze,charging the opened-up piece with liquid and then subjecting the pieceto pressure, substantially as set forth.=

4. As an improvementin the art of separating the laminae otmica, themethod herein described, which consistsin heating'upa piece of mica,immersing the piece in liquid and then subjecting the piece to pressure,substantially as set forth.

5. The method herein described which consists in preliminarily releasingor lessening the bond or force which naturally unites the adjacentsheets or lamina of mica, and then subjecting the sameto the action ofsuitable fluid, substantially as set forth.

6. As an improvement in the art of separating the lamina: of mica, themethod herein described, which consists in opening up the lamiuze of apiece of mica, charging the openedup piece with liquid and thesubjecting of the piece to a rubbing pressure, substantially as setforth.

In testimony whereof we have hereunto set .onr hands.

RICHARD. WI HEARD. RICHARD A. L. SNYDER.

Witnesses:

DARWIN-S. WoLooTT, F. E. GAITHER.

